Commodore 64 systems were the PlayStation of the 1980s and very early 90s. Millions of people wrote their first programs in BASIC on systems like this before moving on to larger, more capable systems that came later. But these devices were relatively cheap, a huge proportion of young boys had them.

Image files for games and other apps can be downloaded for free from C64.com. Some games don't work well on phones that don't have a 'hard' keyboard as, so far, emulator developers have not included support for phones that only have soft keyboards.
Software is still being written for the platform. There is a twitter client (Breadbox) you can run in your C64 emulator if it supports networking. If you want to discover the dawn of cheap home computing, brush up on your BASIC programming or re-live your past, load this app (or one like it) on your phone. Or maybe you were a Sinclair ZX80 fan.