I got these alphabet ice molds on Amazon.
They're fun because I can send love notes to myself in my cocktails, and leave subliminal messages in other peoples' drinks.
The item description says they can also be used in the oven and for things like butter molds and chocolate, but that sounds hard. I'll stick to ice. because I'm cool like that. Get them here.
An index of all of the ice experiments on Alcademics can be found here.