Meh. Do you really think learning programming languages is hard? I think with C, C++, Python, Scheme, CL, Haskell, Racket, and ML under my belt it would take me about a day or two to adapt to new syntax and then you'd be back in the same position you started in.

I just wouldn't worry so much about experienced students or give them something extra to work on if they wanted it. I started programming when I was 9, meaning I had been messing around with Linux, systems, programming languages, and algorithms for a full 9 years before stepping into my first class freshman year. My professors did the proper thing and used the finals from the freshman year CS courses to propel me to upper level courses in my first quarter. Don't try to work against experience, work with it.

Failing that, Forth or J ;P