I've been trying build a model of a beef-burger and though it's not perfect I'm pretty happy with the results, considering it's my first real attempt at modelling.
I now want to add some animation, Ie, the individual parts falling into place.
I've added a collider to my floor, made the bun, burger and tomatoes rigid bodies and the lettuce a soft body. I didn't expect it to work but to my surprise it turned out ok.
I'm working on the problems with the model and texturing but I can't figure out how to stop the jiggle once the parts hit the ground. I also need to make the bun "softer", if that makes sense?
Try keyframing the Linear and Rotational dumping value up when they hit the point you want them to stop. If that doesn't work, I've baked animations before and easied them to a stop with some simple keyframe spacing/deleting.
For the bun you can try to set it to softbody and tinker with the properties or you can use some deformers and fake it out afterwards.