sure you can!,
go on google, search for ruby or sapphire gba rom, download it, open it on gba4ds, if it doesn't work, get a dstwo!
the original games are the pretty much thing, the differences are: old 2d graphics (they were great! not sarcasm) there is 386 pokemons (isn't enough?) and less attacks, and no mega evolution
BUT STILL GREAT GAMES!!!!
ps: also, this thread is relevant:
http://gbatemp.net/threads/what-is-a-poketard.383940/
>insert but the patch walks picture here< (not actually inserted to avoid much abuse)