This type of joke a/k/a the 'con fuse' joins two presumably different ideas to produce incongruity. Very popular with the comedian Steven Wright.
"I put instant coffee in my microwave and almost went back in time."
instant coffee (speed) + microwave (speed) = time displacement
"The prescription for my glasses just ran out" and he grasps about blindly.
Prescription (expires) + glasses (a prescription item that never really runs out) = losing sight.
"I have flip up contacts."
contacts (stuck on eye) + flip up (normally associated with glasses) = incongruous merging of the two concepts.
Look for ways to merge two related concepts into an incongruous way to get laughs using this technique.