iPad going crazy

hi all, I've had an iPad since uk launch day. Totally love it and it is used daily by the whole family. Recently however I am experiencing an issue where the iPad seems to be reacting on it's own with no user input. Web pages will zoom, it will mysteriously navigate around the page. The iPads becomes unusable and allows no user input at all. To recover this position I can hold down the home button and off switch, this brings up the "slide to power off" bar, yet as no input is allowed I cannot slide the bar to affect the power off. I can power off at this point by continuing to hold down the home and power switches.

On restart the "fault" has cleared. This has happened say 5 times since mid December.

Should I do a full restore from back up? Any advice appreciated...