Theremin

Not really a beginner project.

the project will be built around these circuits or similar:

Proximity Sensor

[VCA option 1|http://775elektric.blogspot.com/2012/06/vactrol-basics.html] (scroll down to last circuit)

VCA option 2: [1] (scroll down to last circuit)

VCO option 1 (555): [2]

VCO option 2 (Lamp): [3] (scroll down to pg 3, Figure 2a)