What to get for a 13 year old boy for Christmas?

I am speaking of my brother, and he and I are the same age (if that has any value). He is a videogamealolic, and I would love to get him a video game, but each one costs alot more than I can spend on him (as each immediate family member will have $15 spent on them as this is all I can afford!). He also likes baseball... but I don't want to give him a pack of baseballs or something along those lines because it is unoriginal and has no WOW-factor. This is about all he is into, as he is only a 13 year old, uninterested in anything and hard to shop for boy. Any input would be great! Thanks!

-Oh, and any ideas for a 13 year old sister would be great too! We are both very close, so anything would be great with her, but anything that you believe would shock her and make her really happy would be wonderful advice! Thanks again!