Here's an easy way to tie two ropes securely together, and it has a sweet name: the Hunter's Bend.
There are plenty of applications for the Hunter's Bend knot, and they all boil down to tying two similarly-sized ropes together, end-to-end.
Though it originated as a rigging knot for climbing, it was adopted by a wider range of uses and became known more widely as the Hunter's Knot. Now you can challenge someone with the phrase: "You're not a real hunter unless you know the Hunter's Knot!" Then send them this video.