if the project is driven by an external event (such as someone needs to push a button b4 something happens) then you can use that event to create a random number...
Set up a timer at the start of your program (W/O prescaling) and leave it running, and capture the timer value when someone presses the button, should be pretty random...
if it has to generate random numbers all by itself then i don't really have a clue ... perhaps you should hack some of the code generated by the basic compiler to see how it works
There are various random number algorithms such as the monte-carlo, etc. You can also capture circuit noise and have it trigger something in your software to generate random numbers. Easier said than done, but it does work.