Arduino projects with minimal parts.

Unfortunately I've only a few parts for the arduino. Can you suggest me ideas for projects with these parts.
a few LEDs, a piezo element, a few 555 ICs, an LM35 temperature sensor, a few LDRs, IR recivr ICs (TSOP),

I'm thinking of doing the following

  1. Trying capsense, 2)Make knock detecting door lock and playing tunes with the piezo element, 3)displaying temperature on computer using processing, 4) make processing read twitter feed and send them to arduino for doing physical actions, 5) Connect an old keyboard I have to arduino, 6) Decoding TV remote commands and doing something like lighting LEDs

How about reading the LDR and using the reading to change the frequency of a tone?

Thanks Grumpy_Mike. Thats a good idea.

Taking it one step further, replace the two potentiometers on this with LDRs -

and replace the amplifier with your peizo, it wont sound amazing, but it will be recognisable.

Also this will play through a peizo

Duane B