Being a theoretical physics graduate student, my desk is often a war zone of books, articles, manuscripts and graded papers. This Newton's cradle would go a long way in spiffing it up and giving me something cute to look at and fidget with as I work. As an added bonus, it would be a cool teaching aid to take with me when I go to schools to talk about science.

Edit: Just received another package!! 'The big bang theory' has been my guilty pleasure TV show ever since my high school days and I now have a mug to sip my cup of joe in as I watch it. I love it!!

Toasting my coffee to you, dear Santa!! Thanks a lot :)