Use of Calculators

I wanted to see if anyone had some interesting use in engineering application with calculators, or really hand held computer software. I am using a Ti CX CAS, so I know it has some great features. I feel like I get some worth out of it, but I know i'm barely scratching the surface. I am a Sophmore ME and will be taking classes like dynamics and adanced thermo, so I would appreciate any help I can get.