All Star Batman and Robin(if you want to laugh).
Any of the JLA trades written by Grant Morrison or Mark Waid.
Also, read the first trade of "Hitman", which has a really cool/funny subplot with Batman(and if you want to follow up on it, read the JLA/Hitman crossover comics that came out a few years ago).
"Whatever Happened To The Caped Crusader?" by Neil Gaiman is interesting.
Try some obscure trades if you want to find some hidden gems.
We made this thread to help anyone get their head around Batman comics. The best comics for New Readers, Best Stories of all time, the current comics, trades and timelines check it out