What does he know? I too ran into this issue, which is why I joined the site!
As Snooks suggested, active tasks are best. Leg weaving, getting their leash, getting a drink from the fridge or cooler, getting the mail(if your dog is tall, I really like this trick--teach them to go to your mailbox, stand on hind legs to open the door, grab the mail, close the mailbox, and bring it to you--if you have a small mailbox on your house rather than at the road, this is a bit more complicated), tricks that are in steps....
For example, stop-drop-and-roll is a fun one. Mud and I have recently started considering visiting schools to help with fire safety. A few teachers I know have asked us and we're not sure yet but probably will. (The command I use is "What do you do when you're on fire??")
Or, a dramatic dying sequence---BANG!-limp, BANG BANG!-down and crawl, BANG BANG BANG!-roll onto back. Very cute. ^^
I highly recommend the book "101 Dog Tricks" by Kyra Sundance and Chaucy. It has the basics, but also has a wide variety of creative advanced tricks.
Although it's a basic trick, Mud learned a new one for Halloween---I tell her "Boo!" and she lays down and covers her face. I had skipped over this one in her early training and thought of associating it with this command just recently, and it's actually one of my faves. ^^
Backwards weaving, backwards heeling, Easter egg hunting, get creative! There are many tricks out there. Good luck and enjoy!