Too many ideas

Just wondering what you do when you have heaps of ideas all popping around in your head?? I'm not a fast writer either on paper and the computer so in my head i get further along then what i have on the page, i hate to stop my thoughts (because i can never really get them back or where they were going) but otherwise i cant keep up with myself. Should i buy a voice recorder then write in later? What would you do? Thanks.