I don't think any age is really too old, but it is hard for me to imagine why anyone well into their 30's would *want* to hang out at clubs.
Going out to eat or having drinks with friends is nice, but the typical "club" scene just seems like it wouldn't appeal to people past mid twenties. If I'm out clubbing when I'm 35 or 40 I hope some of my friends will do an intervention.
