Depends how mobile you are, but on the Lizard peninsular you've got a few sites to choose from:
3 Brothers of Grugith (behind the petrol station)
Crousa Common Stones
Wendron 9 Maidens (only 4 or 5 left)
Burras Menhir

Further afield you can get into Penwith proper and the treasures there are too many to list here. Check out mine, Paul1970 and PureJoy's weblogs for further details...