Ones that actually glow!!
Here is a step by step on how to convert them.
Step 1: Parts List
2x Luxeon 1 Watt Red LED: www.sparkfun.com/commerce/product_info.php 4.95
2x DPDT Slide Switch 275-007: www.radioshack.com/product/index.jsp 1.99
6x 393 Coin Cell Battery: www.amazon.com/1-55V-Silver-Oxide-Watch-Battery/dp/B000BT0B36 1.00
(I actually bought a 30 pack of assorted ones here www.sciplus.com/category.cfm/subsection/13 no such thing as too many batteries)
2x brass tubes unknown sizes one with ID Matching the other's OD so they slide over each other and large enough to contain the batteries 1.99*
Package of 10 OHM resistors: www.radioshack.com/product/index.jsp .99
A messy workspace (helps with creativity!)
*OD tubing size is 3/8 of an inch*