A cheap alternative to commercial raceways. Comb bindings are designed to hold large amounts of paper, which is heavy, so they're stiff. They're, um, combs so branching is easily done without cutting. And they're cheap and readily available.
Step 1: Get Some Comb Bindings.
You can get them at any good office supply store. I've seen bags of them on-line really cheap. I work in used books so I can get them for free from the rejects.
Step 2: Fix Them Where You Want to Run Your Wires.
You can use a staple gun or double sided tape. I wouldn't bother with glue. Finding a glue that will stick to the plastic they're made of and another material would be pretty difficult.
The plastic isn't the most penetrable in the world. If you use the staple gun, the staples will penetrate the comb and wood but you will have to drive them the rest of the way.
Step 3: Run Your Wires.