A few popular ones:
- "They've seen the ark on Mt. Ararat in aerial photographs!" Well, no, they haven't. A quick Google will show that further investigation revealed all these sightings to be of various lava formations.
- "Space scientists had to account for the missing day in Joshua!" Well, no, they didn't. Snopes has an entry on this one.
- "When the Greek patriarch in Jerusalem observed Easter by the New Calendar, the Holy Fire didn't come down!" This one I did a bit of research on. Inevitably the reference is to the same account, and this account follows classic urban legend form of putting the supposed witness somewhere out of reach. Since hundreds of people would have seen this, nobody should have to rely on the word of an obscure monk at an unreachable monastery.
- "Easter is pagan!" Well, no, it isn't. This can be traced back to a source: Bede says (or speculates) that the word "Easter" comes from the name of the goddess "Eostre". Well, modern researchers (e.g. Ronald Hutton) tend to doubt that there was any such goddess, and point out the obvious common component: the word "East". At any rate, the name for Easter in most languages is derived from "Passover" or "Pesach" (to use the Hebrew).
It's not hard to research tales like this anymore, especially if you're posting from a computer on the internet! While you're at it, you can check on the illustrations in the sermon on Sunday morning.