a couple of games I have done in the past are
1. the dreaded if the lee does something.. (such as curse, snort, squeal, say a certain work) you can start to unlace, one of their laces, and you continue that, till the laces are all unlaced, then you can tickle the lee on the feet (great if the lee has a pair of vans and has ticklish feet or the feet is one of their worst spots) it adds a certain 9 lives element to the game.
2. Another one I've done, is dangled a high heel, or dolly shoe, on a lee's toes, and tell them they have to see how long they can stop their heel or dolly shoe from falling off their toes, of course you tickle them in all other places, but not their feet, till they lose the game!
3. I've recently done done maths questions, and asked the lee maths question and tickled her while she is trying to work it out, if the lee gets the question wrong, you target one of their most ticklish spots for a few minutes and then start the game again.
4. finally for a bit of spice if you fancy it, I've done the same rules as the first game I mentioned, but changed it to, they lose an item of clothing, and yeah, as the tickling goes on more of their spots get more accessible and exposed so in theory get more crazy for them lol
I mean who doesn't enjoy a good tickle game!? as a video gamer, I know I do! I've done all the above before and they do bring a fun to a vanilla relationship that is for sure! happy experimenting!