Hi all, how do I get a capacitor to charge up and discarge repeatedly without using a manual switch or a 555 timer (using only resistors, capacitors, transistors and silicone diodes)?

Try this site:

Howto build an oscillator circuit - Wikihowto: a howto site anyone can edit

There are also some ideas here:

http://www.google.com/imgres?imgurl=...num=5&ct=image

You will undoubtedly have to amplify the output signal (use a transistor configured as a follower) to get enough current to drive the LED