We came across this brilliant puzzle on Plus Magazine, and they've kindly allowed us to share it.

Two people have asked you out for a date and you decide who to go with by flipping a coin. The only coin you have, however, lands heads with a probability of $0.75$ and tails with a probability of $0.25$. How can you a use a series of flips to decide who to go with so that both people have the same chance of being picked?

Post solutions below!