Where to put $$$$

Briefly, I consider my myself financially informed but would like a few opinions.

Mrs. Cptigger has some savings that is just sitting in a bank, about 20k. She has a desire to put that into a CD. I find CD's boring and since we are young I'm trying to convince her to take more risk with the idea of getting a better return. simply put, where should I put this $$? Will not need it for years fwiw.

Thanks in advance.