There were many things unforgettable of that trip with my close friends.
We visited all the ancient temple ruins for at least three days. I have seen the enormous beauty of the temples which made me wonder on how were they able to construct them during ancient times.
We tried the happy pizza, or pizza with marijuana, which is legal to eat in Cambodia. There was no effect on me though it seemed one of my lady friends had it. I can't explain why I am unaffected.
We visited Tonle Sap lake, the largest freshwater lake in Southeast Asia, seeing the lives of the people in the floating village. We saw how people live adapting to the environment.
It was probably the cheapest trip I had, where one USD is highly appreciated. You can go around and pay in USD bills.