I saw that you mentioned geocaching on your site as a great date idea. Well geocaching may be fun but it can be expensive to get a GPS and it's not really little kid friendly. Let me introduce you to Letterboxing *cue heavenly choir*. It's like a treasure hunt and your kids will love it! I've done it with my sister's family, my sister-in-law, and I introduced my cousin to it. It's equally great for a date or as a family night activity. You can do it on vacation as a way to break up those long car trips. When your kids are older they can do it for a day activity on dance nights. Your poor college kids who survive on Ramen noodles, saltines, diet coke, and gum can do it on dates.
Every year for Mother's Day we go to Moab and hang out at the local KOA. The national parks there are fun and it's not too hot to enjoy them. But another thing we go there for is that there are a TON of Letterboxes there.
So here's what Letterboxing is. Someone hides a box and in that box is a stamp, often a homemade one, and a pad of paper. You follow clues to find the box. When you find it you take their stamp and stamp it in your Letterboxing book, and you take your stamp and stamp it in their Letterboxing book. You'll soon have a book filled with interesting stamps from the Letterboxes you've found..kind of like a passport.
Your kids will look through the book and remember the cool clues and fun times you had while you were looking for them.
We recently had two weddings in our family. The weddings were early in the morning with receptions later in the day. We had 5-6 hours to hang out in between. I don't know about your kids but that was PLENTY of time for my kid to get whiny and cranky and NOT show up happy in the reception pictures. Knowing that, and after the price of hotels, dresses, ties and all the other things that go with a family wedding...I was not looking to add to our expenses. So I printed out several Letterboxes and we did them during our down time. It kept me, my husband, and my kid happy, we got out of helping at the reception AND having to hang out with the in-laws, AND we were building happy family memories! BONUS! (You're also outside walking around..which burns calories and helps your children think that maybe this healthy lifestyle stuff isn't so bad.)