We’ve done the whole "happy hour" thing, it really has run its course. We’re a middle school faculty of 30, and not really looking to spend more than 400-500 bucks. We were looking at ideas such as bowling, ropes course and the like.

You may want to have a look here: http://www3.telus.net/chase-games

This site describes an Amazing Race party plan that is great for a birthday party, sleepovers, scavenger hunt, etc and is designed for kids aged 10 – 16. The “legs” of the Amazing Race party plan sell on eBay quite cheap (like $5). Good Luck!