stars and rewards

I think the gold stars, with some reward at the end, are a really useful incentive. Going to the gym has seemed relatively easy, though*, so I'm thinking I should switch them to something that's more of a challenge.
The area I'm still struggling the most in is with lab work, so it would be good to tie it to something explicitly work-related. I'm having trouble thinking of something quantifiable and attainable, though. I'd like to get to lab earlier, in the hopes that getting a good start would boost my productivity during the day, so I could make the stars contingent on getting to lab by a certain time (or leaving the house, at least, so I don't lose my star due to the vagaries of public transport). Or I could set a specific length of time I have to work per day. That could get messed up when I have meetings or seminars all day, though. The thing that seems most definable as a goal is to read a paper every day, but it's also the least important, perhaps. There are definitely enough worthwhile papers that it would be useful, and maybe it would help me get more involved in my project, but I'm not sure it's the most important thing. And again, it seems attainable, and therefore perhaps too easy.
The other thing I've noticed, as I've improved the rest of my eating habits, is that I'm still eating way too much sugary stuff, so I'm kind of thinking of copying StyleyGeek's no sugar for 30 days plan, but that probably isn't such a huge priority.
Anyone have any other ideas for useful goals? Or opinions on what I've mentioned? I think I can keep going to the gym without having stars depend on it, but I'm also thinking of just adding the new thing on top of going to the gym. Is that a reasonable idea?

I'm still trying to think of rewards, too. I like Cee's idea of a massage and I've thought of a few books/CDs I'd like. Shrinky also had the idea of making each star be worth some amount of money to spend on whatever I like. I think the amount of money I'd be willing to spend on rewards might not look so encouraging per star, but maybe just setting aside some money to specifically spend on fun stuff would be good.
I'm also thinking of having some larger reward for 90 stars, and maybe 360, so that I can make this a long-term project. Now that I'm doing project 365 again, I keep wanting a smaller camera that's easier to carry around (although then I would miss my 12x zoom). I still want an ipod, too, but things like that seem far too frivolous or self-indulgent to actually buy for myself (I have a perfectly good camera and a little mp3 player I don't use often enough to justify anything better). That might be a good criterion by which to choose larger rewards, though.
Ideas/votes for rewards?



*Maybe it's just that anything I actually manage to do must, by definition, be easy and not worth feeling proud of myself for...