The jeep safari's are a 'must do' - really good day out, if you dont mind getting dirty and wet.
We always do at least one boat trip, which gives you a day out, including BBQ lunch, but I would recommend
asking for a boat for no more than 30 people, its like a cattle market with any more.
We love to see some of the area, so if its not too hot, just wander, or do the walk to
Marmaris and maybe get the water taxi back (I think the water taxi may be 10 lira per person now, but well worth it.)
If you want a good laugh, and aren't easily offended, the Stella Show at Harmony Bar is very good.
There are quite a few excursions advertised on here if you want to take advantage, but beware, unless they can
get enough people, they wont put them on. We've been disappointed a few times.
Have a wonderful first trip!