My aunt is being so kind and letting my family use her timeshare at Tahoe in June (It's at Incline Village). It has been about 15 years since I have been there last and we are trying to decide what to do. What do you like to do at Tahoe or what have you done that was fun?
We loved it when we were kids. You can also rent rafts and do a ride down the Truckee river. The river is very mellow (so you don't need to worry about big rapids). I don't know what the river will be like this year since we aren't getting enough snow or rain, but it is a fun activity. I can't remember how much the boat rentals are currently, but you get a boat, paddles and life vests and they pick you up at the end of the ride down the river and bring you back to the parking lot. Pack a lunch and stop to eat along the way and let your kids swim- it can be lots of fun! There are also sooo many beautiful hiking trails (Eagle lake is beautiful, the rubicon trail is beautiful- if you are interested, let me know your hiking level and I could recommend some good ones). The Taylor Creek area is a great place to walk with little kids. You can walk a little path and learn about plants, animals and go through an "underground" viewing area where you can see the creek and the fish. It is also right near the Mt. Tallac historic site which is fun to walk around and learn about the history of Lake Tahoe. 
