Like countless others have said already the people at the gym are more concerned with themselves than with you. Most gyms will give you a tour and possibly give you a free session with a trainer just telling you how to do some basic things in the gym. One workout that you can make as hard or as easy as you want (good for beginners to test their level without worrying about looking foolish) is the following:
Treadmill w/incline
-Hop on and set the speed to about 3.0 (or whatever you can handle) and do a 5 minute warm up at 0 incline.
-After warming up start increasing the incline by .5 percent each 1 minute for as long as you can, keeping the speed at 3.0.
-Once you have gotten to as tough of an incline as you can handle start decreasing the incline by .5 every 30 seconds using the same 3.0 speed until you get back down to 0.
-The finish out a 5 minute cooldown at 0 incline and 3.0 speed.
***This workout can be really hard if you push yourself!***
If all else fails you should see if you can solicit any of your buddies to join with you!