Does any one have ideas for any non-boring platonic activities I could do with my ex-boyfriend?

This guy and I dated a little over 2 years ago when we were both freshmen in college and have not had much contact other than the random text or Facebook message. We were friends for 3 years prior to dating and when the relationship did not work, we decided that we would just go back to being friends. I do not think I still have feelings for him - but then again, we have not seen each other in ages. We have planned to do something together this weekend since I will be home for Labor Day. I need help coming up with fun neutral things that we could do that would not make it seem like a date or be too impersonal like going for a movie. Any ideas?