A simple holder for a simple thermometer from dealextreme. It's parametrized in OpenSCAD, so you can easily adapt it for other similar equipment.
I use mine to read the temperature of my manually controlled heated bed, and you can't have anything like that attached with strips when you have a 3d-printer.
The sensor itself is taped to the top of the bed glass plate, and provide adequate accurate readings. About 5-10 degrees off I reckon.
As you see in the picture I printed it a little on the small side, so it bulges a bit.
If you don't have one, you can order one for ~3$ here: http://www.dealextreme.com/p/digital-compact-lcd-thermometer-with-outdoors-remote-sensor-15553?r=10492979
You can change the polling time of said thermometer to ~8 seconds by cracking it open and bridging the pads marked "SW3" with some solder. See this thread at dealextreme forums: http://www.dealextreme.com/forums/Default.dx/sku.15553~threadid.398905
Measure your thermometer and compensate for printer accuracy in the OpenSCAD file.
Set skeinforge to make "infill in direction of bridge". Print, then cut off the little bridge support on the end of the clamp.
Clip in the thermometer, and bolt it to your Mendel.
You will now smile every time you read your bed temperature.