A lot more than you could do with "just C". Can you imagine C without any libraries and #include headers?

I have a crippled Perl 5.6.1 on my Sharp Zaurus PDA. Some modules are there, others aren't. It's a big enough pain in the rear that I've mostly gotten away from using Perl on the Z, and instead, use the Z as a perldoc reader and Perl CD Bookshelf reader (I've got my CF card loaded up with those gems).