There's lots of projects out there for using Capacitive touch sensors.
This instructable was inspired by someone who made a capacitive touch Arduino piano.
The problem is how to easily make a touch pad, especially if you want a thin or flexible pad or don't know how to solder.
Here is my solution to that problem.
At almost any local hardware store, you can get Aluminum Tape.
Sticky (and not so conductive) on one side, shiny and very conductive on the other.
Gather your wires, and the tape.
Step 1: Prepare the Pad
Cut a piece of the tape the size of the pad area you want, plus an extra couple cm at one end for attaching the wire.
Peel of the protective backing, and lay the pad down sticky side up.
Step 2: Prepare the Connection
Make a small fold on the end where you left extra for the connection.
Fold it so it's sticky side to sticky side.
You should now have a pad that is mostly sticky side up, with a conductive strip on one end.
Place your wire on the sticky tape one half the width of the conductive strip away from the strip.
Fold the conductive strip over the wire - it should be in the middle of the conductive strip you are folding over.
The sticky part will hold the conductive part to the wire.
You should now have your sticky pad with the wire firmly connected by the sticky side of the tape to the conductive section.
Step 3: Attach Your Pad
Now you can place the pad wherever you need it.
It can be acrylic, wood, cardboard, coffee cup, pencil, or even paper. This stuff sticks to pretty much anything and is quite flexible.
Now just hook it up to your project!