Homemade methods for interfacing a Servo with LEGO bricks I'm looking for non-destructive way to structurally attach a standard servo with LEGO bricks.  I'm interested in answers for either Large, Medium or Small size servos.

I'm using LEGO Mindstorm/Technic bricks to prototype all kind of robotic projects and I often use non-LEGO parts for the electronics (e.g. Arduino, Servos, LEDs, ...).  I'm always trying to find better ways to integrate those non-LEGO parts without damaging the LEGO bricks.

I'm aware that there are some commercial adaptors available on the market but I'm interested in creative homemade solutions (low-cost to no-cost).

For example: here is one way to attach a medium size servo to a LEGO Technic beam:
The best solution is to create custom LEGO-compatible bricks that your servos (or other parts) fit into. This can be done by: 


modding existing bricks with knives, glue and other tools
building bricks from other material (wooden LEGO, formed with Fimo/Sculpey...)
building bricks with a 3D-printer (for instance see the LEGO category on thingiverse). There are online services to print your designs if you don't have a 3D printer (yet ;-)


Each strategy is worth another question here at bricks.SE.