You'll find lots of places to exercise your cleverness around here, at any time of day. I recommend heading over to Fragments and Feedback to read some submissions and offer your feedback. I always learn the most by critiquing the work of others. Have fun!
Don't worry about impressing anyone with clever greeting posts. It is the writing of your stories that matter!
I'll just echo sojoyfuls sentiment, you will learn more from critiquing the work of others than having your own work critiqued. So I recommend giving critique as much effort as you give your own work, and you will be doing yourself and the author of the work a great service.
See, I shamelessly co-opted sojoyfuls sentiment, I'm not being clever either.