What is this bar thing across the top of almost every page?

That bar thing is the Gimmee Members site playlist. Using it, you can get to every video on the site.

Across the top are the category tabs. If you hover your mouse over the tabs, starting from the left to the right, you'll notice that they start moving across the top, revealing all the different categories. You can scroll them back to the beginning again by hovering the mouse over the left side of the tab list. (Go ahead, it's right up there! Try it!)

Under the tabs are the video teasers. They work the same way as the tabs, scrolling from side to side as you move the mouse over them. Once you've scrolled all the way to the right, you can click the little arrow to load the next group of teasers. Naturally clicking the left arrow returns the previous group.

To view all the teasers, choose a category tab and click on it. Then peruse the library of videos, choosing the ones you want to watch. When you want to move on, just choose another category by clicking a new tab.