I've always enjoyed distraction tasks- you could make her memorize something (long and difficult, like Shakespeare or the Declaration of Independence) and then make her recite it back to you while you stimulate her (or hurt her, depending on your cup of tea) in some way, and for each mistake she makes you mark a point, and then decide how you will dole out those points. It could be one lash per point, or "5 points equals one punishment, 10 points equals another (more severe) punishment", and so forth. Meanwhile she's actually learning something, too.
I've made my boy watch movies while edging him the entire time, and then give him quizzes at the end about it- you can start easy and go up to very difficult ones, like "what was the main character's little brother's name? (which was only mentioned once)" Very fun, because you know the parts that have the answers are coming up ahead of time, so you can increase the distraction appropriately.
Multitasking is also very fun; I've made my boy try to draw (he is a fairly decent artist) while being stimulated and those pictures (which are horribly lousy, as far as his art goes) are so much fun to look at, because I can always see the point where he gave up, the pencil leaves this weak little trail across the paper.
I've also made him fail at video games he's normally very good at...I'll give him some score he has to reach or distance he has to travel and then make sure he fails just before hand. Oh, and there is a reward for success, too, which he has obtained a few times.
One thing I've always wanted to do, but never will because I'm too lazy, was to learn a second language and then tell him he can only use that during a session- but I'd have to learn it too. But if you already know a language she doesn't, I would imagine that could be amazingly fun.