Most everyone has ironed out what they want to give up for Lent, but just in case you're still looking for ideas, may I offer a suggestion?
Give up work on Sundays.
I am serious. Set aside that extra paperwork that you brought home from work. Let the laundry pile up. The home improvement project can wait. There is no need to get the cleaning done that day. No errands. If a possible commitment comes up for a Sunday, say no. The yard work will still be there Monday or the next week. The grocery store, the mall, whatever other shopping centers will still have their doors open to welcome you on the other days of the week. I do not want to hear, "I'd love to, but I just have to get x, y and z done." Give it all up, let it all go.
God made the sabbath for man, but maybe you don't feel can afford to take a day of rest. So don't do it for you. Do it for Him this Lent. What sacrifice does He love more than obedience? He gave us a commandment to keep holy the Lord's day. Be obedient to that this Lent.
It is hard to take a day of rest when you're used to just pushing yourself and trying to get it all done. Maybe a lot of the work that you're trying to do is for Him. You may be one of those people that's constantly volunteering at church or be a part of this that or the other ministry. Or you're trying to live out your vocation as best you can and you need to get those things done in order to be the best wife, mother, teacher, etc. This one day, set aside all of the tasks associated with those things. (Granted, it's a different story for pastors, since Sunday is the day that they are carrying out one of their primary tasks.)
On the one hand, telling people to give up work on Sunday for Lent sounds a little like telling people to give up lima beans for Lent. If it's something you want to give up, it's not really a sacrifice, right? Wrong! In this case, this sacrifice, like any good Lenten sacrifice, is hard to do. It's hard to let go of the tasks that will fall apart without our capable hands. It's hard to give up this whole wonderful day that we want to use to finish up all those projects that are weighing on us. It's hard. Do not think that it will be easy. But it will be worth it. I do have a couple of suggestions to help you be successful.
1) Commit to it. If you make a half-hearted, pansy-a**ed attempt at this, you will fail. I guarantee it. Go all in.
2) Pray. You will need prayer to make this happen. If it is not a part of your life at this time, you will not be able to do it without prayer. Monday through Saturday, my suggested prayer (to be prayed when you are stressing out about all the things you have to do) is "God, please help me get the things done that need to be done." On Sunday (when you are stressing out about the things that you think you have to do right this moment because it is the only chance you think you will have to do it) my suggested prayer is "God, help me to let this go into Your hands and not think it is all dependent on mine. Help me to trust You for this task."
3) Plan ahead. If you can, plan and prep the meal the day before. That way, you will not need to make a last minute trip to the store. You can throw the meal in the oven that day instead of trying to prep it.
4) Prioritize. If you are like me, the weekend brings with it a monster list of things to do. Figure out the top two things that absolutely have to be done, and start with those. Then go from there with the time you have left.
5) Consider sundown to sundown celebration. I think the most important part of a sabbath rest is that you get 24 hours of rest. Some people need Sunday evening to get things ready for work. I think that's fine. You work all day Saturday, but when the sun goes down, you stop (or pick a time like 7 or 8). Rest begins now. Spend some family time, watch a movie, read a book, take a bath, go out, whatever evening kind of activity helps you recharge. Then on Sunday at sundown, you can start to get things organized for the rest of your week.
6) Learn how to say "no". People will still ask you to do things on Sunday. If it's not a relaxing and fun social engagement, tell them honestly that you can't because you already have plans. They do not need to know that your plans are to relax in whatever way is most fitting for you. Trust me, those plans to rest really are important and necessary. You don't need to feel guilty when you tell people this.
7) Speaking of guilt... It is very hard to let go of that nagging feeling that you should be doing something "useful" right now, instead of whatever relaxation you are doing. Let it go. Far from being guilty, embrace the fact that you are doing exactly what God has asked of you for this day.
In case you are not used to celebrating Sunday, may I offer some suggestions? I always think a special breakfast is nice. It doesn't have to be fancy (because you are resting, remember?) I'll buy myself a little chocolate milk (it's the simple things that make me happy) and something easy for a hot breakfast. Church is a must. We need that communion with God and each other. If possible, dinner as a family is ideal after church. Beyond that, it's whatever helps you keep a holy day of rest. Naps are nice. Maybe you like to watch sports or play sports or just go for a walk. Being in nature is an awesome way to spend a Sunday. Growing up, my family would often go our separate ways after lunch (half of us fell asleep for at least part of the afternoon) then in the evening we might play a game or whatever. Everyone's different, so do what works best for you and your family.