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 (http://howto.wikia.com/wiki/Howto_build_an_oscillator_circuit)

There are also some ideas here:

http://www.google.com/imgres?imgurl=http://www.tpub.com/neets/book9/0115.GIF&imgrefurl=http://www.tpub.com/neets/book9/35c.htm&h=360&w=331&sz=4&tbnid=_eLWPdBeFSXvpM:&tbnh=121&tbnw=111&prev=/images%3Fq%3Doscillator%2Bcircuit&usg=__PxILbl7TFQ_XmdxvC2Sf8md4BAY=&ei=ggtOSo2JEou2NsLc_e0D&sa=X&oi=image_result&resnum=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