If you live near a Dave and Busters, they have a deal where you can get $10 of free play, valid now through the end of May!
Just sign up for the coupon here: http://freeplayday.com/
It says you can't combine it with the eat and play combo or events, but doesn't say it excludes their Wednesday half day play!
Also, if you have a Power Card, you can register it for a free $10. I am not sure if you can combine these but it's still a good deal to sign up for!