Definately check out George's Pink Palace (hotel/resort) in Corfu. It is like spring break there "Europe style" with people from all over the world from 18-30 years old all summer long. I went in '95 and it was $17/night and that included breakfast and a nice room with view of the water. The hotel is about 100 yards from the water with very nice warm clear blue water and plenty of hot women and topless tatas. I got laid there too

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Then check out Santorini if you can. This was my favorite place in Greece. Either get there via ferry or it would be best via plane as it is quite some distance from Corfu/Athens. Rent motorcycles there (80cc or 125cc dirtbikes) and ride around the island (must do). It is spectacular and has red/black/white sand beaches. The sand is actually small pebbles that are very smooth..... since it is all volcanic. I stayed at a place called the "Diamond" which was very nice and traveling with 3 of my buddies it was about $22/night but it was brand new and PIMP to bring the ladies back to. I stayed a week there and it was so relaxing.
I would check out Athens for about 2 days and get the hell out of there as it is pretty dirty but has a lot of history you truly must see.
Get a youth hostel card and stay in youth hostels wherever you can to save money. Make your own lunches and eat at restaurants as little as possible. I brought a glad storage container, cutting knife and real fork, spices (pepper/salt/cayenne/sugar/paprika) in a small container you can get at REI for about $3 already filled

. We just graduated from college and were broke and did it on the cheap spending about $40/day for 8 weeks like you plan. I would suggest checking out Italy as well since it is totally cool also and close to Greece. The southern most place in Italy is Brindisi and it is the port where the ferries leave to go to Athens. Kind of a dumpy place but we found a killer restaurant for cheap there.
Bring a flask to carry in booze to mix with Coke at any nightclubs you go to in order to save money and have cocktails before you go out or it will be pricey.
Have fun and bring lots of suntan lotion and definately jimmy hats

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-GNX7