You asked "what is the weirdest", not "have you ever eaten anything that the majority of Americans would consider weird?" So the thread could go on for a long time with answers like, "I once had a peanut butter and jelly sandwich."
But yeah, I've not really stepped outside of what's considered "normal" food. But I enjoy some odd combinations.
A BLT made with peanut butter instead of mayo.
There's an Italian (at least I was told) treat called an Easter salad, it is a stack of (from the bottom up):
Provolone cheese
Genoa Salami
A circular slice of orange
A slice of hard boiled egg
A black olive
Drizzle with olive oil
You eat it by sliding the stack from the orange up, to one side, and folding it in half so each bite gets a bit of each component.