I am interested into programming with different languages besides Ti-Basic (like Java, C, and Python) on my Ti-84 plus calculator. Does my calculator support this, and if not, are there any calculators on the market that would be able to do this? Thanks in advance!
(The idea is that when I don't have access to my computer at home, I could just pull out my pocket calculator and start programming and testing out some algorithms on the go that come in mind.) 
It doesn't have to be a calculator, just something cheap and programmable and something I can carry around in my hand.
After a little research, I found some some hand-held "pocket" devices.
The Palm m500 has a JVM to program java on. There apparently was a website that had an SDK for C, but the website was removed. 
In regards to calculators:

TI-82, 83, 84, 85, 86, and related models all support TI-BASIC and z80 ASM.
TI-92, Voyage 200, TI-89, and related models all support TI-BASIC, C, and 68000 ASM.
TI-nspire supports TI-BASIC and Lua.
HP 50g supports RPL (User and System), ARM ASM, Saturn ASM, and C.
HP 49, 48G, or 48S, which support Saturn ASM and RPL.
Multiple Language Programming on Ti-Calculator