Ellipses

This is a little different than my normal forum posts, but I wanted to see if anyone had some ideas for me.  I'm covering ellipses with my Algebra 2 class and they are hitting a wall.  They did alright with circles and I've tried to show them the similarities between the shapes, but today we were writing the equations for an ellipse given different information (endpoints, foci, length of major/minor axes) and it was one of those days where the students weren't with me and were dreaming of being at home asleep. 

With other topics I know of some different ways to approach ideas.  I'm lost right now on a different way to teach kids how to write the equation for an ellipse other than showing them how to find the center, a, and b, given different information.  Problems where they were given endpoints and foci were the most difficult.  I'd love to slow down and cover each type more in depth but I'm getting to the point where I need to make sure we hit everything before June.

I'd love any ideas or even links or videos that you think would help a struggling student or class of students.  My max class size for Algebra 2 is 11 if that helps.

Sean