Chaweng Beach is definitely the most happening of the beaches. There are many tiny restaurants serving delightful treats and fresh homemade Thai food. No frozen food is being served here! From fresh coconut and corn on the beach, to spring rolls and curry... there is something for everyone!
There are also tons of little shops. If you need it, or even if your don't, they have it. One souvenir that is worth picking up in Samui is a wood carving. They are generally square or rectangle, and depict the face of Buddha. I have seen the exact carving sell in the US and Canada for $55! You can grab one for about $7. Some have a gold brush look to them as well.
Just off of Chaweng Beach, you will find Muay Thai, or Thai kickboxing at Samui Stadium. Fights start at 9:00 p.m. Tickets are about 1,000 baht, unless you get a local to buy tickets for you.
Initially, I was not sure if this would be interesting to me since I don't have a martial arts background. Yet, I quickly come to find out that it is an experience not to be missed. There were little boys that were 6 years old who were fighting as the opener.
There are about 10 fights in all, with the last, the most experienced fighters. There were a group of men standing close to the ring shouting at the fighters when they fell. Apparently, there is quite a bit of betting that goes on at the fights. But I wouldn't recommend betting with the locals, because you may get yourself into something that is not so easy to get out of.
Don't forget to get a traditional massage while in Thailand. Massages start from $5 per hour. It is very relaxing and definitely a great bargain. When you get there, you will asked to change into a pair of fisherman style pants that tie in the front and to wait in a private room. Don't be alarmed, this is totally normal. If you are not in to a full body massage, try getting a leg massage or even a neck and back massage. There is a great massage salon just across the road from Chaweng Buri Hotel.
The massage salons generally do laundry as well. Be sure to pack light and just get your laundry done there. It is about $1 per kilo for laundry to be washed and pressed. Turn around time is usually a couple days. They also have an express service for a slightly higher cost.