They're certainly nothing all to look at, disturbingly very similar looking to slightly melted Gummy Bears. But those are custom shaped sound-isolating ear buds, perfectly formed to fit the ears of a Make editor's canals, combining some in-ear earbuds with a putty-based ear plug kit for not all too much money. Watch the video of how he did it below.
Make: Project's Collin Cunningham used a $7.50 kit and some old in-ear headphones with the stem-style that allows for interchangeable rubber inserts. Looks fairly simple, though we'll stick with our over the ear cans for now (these might be worth investigating for running duty, though).
Check out the complete step-by-step tutorial at Make Projects and get ready to watch some awkward-great geek swaying and dancing during a part of the tutorial video.