Yeh if you do opt for an Xcelerator, leep in mind what Lon said, you can only do each ride once with them. If you go to one of the last pages of the "Quick questions" thread on this forum section i posted all the rides you can get on with them and what entrance you use etc.
Im gonna ask a question here actually, on your behalf. Are there any special birthday hotel packages or anything you can buy from AT? Cos when i had my Xcelerator pass, as i went into Nemesis the ride host there asked me "so whos birthday is it then?". I dunno if he just meant did someone buy me the passes for my birthday, or wether you get them as some kind of special little present from AT if they know its your birthday or what, but if the latter was true then that would be something to look into.
Alternatively, stay in the hotel and hope something in your room explodes, thats your Xcelerator for the day paid for 8)