Gas Law Experimental Apparatus
Some of the things you have at your disposal:
Besides the normal Vernier LabPro, Laptops, LEGO NXT, etc.
Hot Plate
Bunsen Burner
Masses
Ice
Beakers
Vernier Gas Pressure Sensors
Vernier Direct Temperature Probes
Go Temp Temperature Probes from Vernier (USB plug)
Vernier Stainless Steel Temperature Probes
MyTemp which uses MyDAQ. Examples
Here are some links to the Vernier Site with some suggested experiments:
Gas Pressure and Volume Experiments
Based on the above, you should be able to also figure out a way to vary volume vs temperature.