For some fun at your next gig, check out the #1 Song Database to see what the #1 song was on a certain date.
This tool can come in handy with anything which has a date...and that's just about everything.
For example, if you're got a fan you want to honor, find out his birthday and play the #1 song from the day he was born?
Of maybe go back in time and play the #1 song from 20 years ago?
The possibilities are limitless, and it's a great way to do material you wouldn't normally be able to, so use your imagination. Your audience will appreciate that you're doing something other than the same old show.