Who cares about hot-tub time machines? You can't find the pool chemicals in the Triassic anyhow. We want a grad-student or academic-librarian mailroom time machine, because we KNOW grad students and librarians squirrel away essential survival materials in mailroom fridges, cubbies, and desk nooks and crannies. If you want the One Week, One Tool team to build a Grad Student Mailroom Time Machine, upvote this idea NOW!
Idea No. 2