Tough request, as most people here don't know what kind of projects your seniors have done. 40-50 projects... we hate to play 'guess-and-reject', much more productive things to do with our time. We build projects too...
Since you are learning the chip, and in school, I'd suggest a project that challenges you a little. Think about things that interests you, and maybe something you could use.
I just start with microcontrollers (Atmel) last December, but have two complete projects (need to revise the PCBs). Use search here, for your chip, remember several post, but don't use it myself. Google search engine will give a bunch of links. I know there are several site that are dedicated to your 8051.
Oh, don't let some replys you get discourage you here, many are a little touchy on the homework subject. Most don't mind helping with work in progress, just don't like walking students through it, and having to explain every little detail,