Party Ideas Needed

My "babies" ( boy/girl twins) are almost sixteen!  I am planning a surprise party for them.  I've reserved a banquet room at a local Italian place, although I don't think I can even begin to fill it with people.  It holds 60, but I'm thinking we might have 30 there.  Wish I could get in touch with more people.  Thank goodness for facebook where I can message some of their friends to invite them.

Here's what I have in mind.  A very simple centerpiece on each table that consists of a clear glass or vase filled with colorful jelly beans (maybe an ice cream sundae type glass) with 3 colorful straws in each glass, and attached to each straw, a colorful "flag" or pennant shape that I cut with my cricut.  Something like this, but thinner with the straws in it.

Maybe some tinsel-type streamers on the table.  Streamers hanging, a birthday banner.  I'm making a board for each of them that has their picture in the middle and their friends and family can sign it.  A regular cake and a cookie cake.  Italian dinner buffet.

Entertainment... I'm making a slideshow of their life.  Hope it won't embarrass them too much.  Someone suggested doing a roast and toast where I make them sit on stools next to me and I talk about funny growing-up stories.  Someone else suggested a "trivia" type thing where I ask the guests questions about them and maybe give a candy bar or something to the person who gets it right.  I don't know.  I guess I also need to do a CD of music to listen to.  I'm just not sure about the "roast and toast" or the "trivia."

Please help me with other ideas!  Are these ideas lame?  What else could we do?  Wish I had time to do a contest so I could get lots of ideas.  Leave me a comment, please.  I appreciate all suggestions.