I've almost died laughing reading about 'Mary, full of grapes', but in other languages that prayer also causes some trouble;
In Dutch, we say 'Mary, full of grace' as 'Maria, vol van genade'. But since I didn't listen too well as a kid, I always thought they were saying 'Maria, vol van garnalen', which litterally means 'Mary, full of schrimps'.
Go figure.
A childhood belief about prayers

others believed things like this
- My brother used to say, "Hail Mary, Full of Grapes..."Anon
- "Hail Mary, full of grapes, the lord is a tree"— reenie
- "Hail Mary full of grapes" And "The Fruit Of The Loom, Jesus."— Silly Little Girl
- I thought "Virgin Mary" was actually "Verge 'n Mary" and that Verge was a nickname for Joseph. — Rachel
- I used to think virgin mary was actually 'virginia mary'Anon
- In the Hail Mary prayer, I used to say 'Bless a dark fowl among women' rather than 'blessed art though'Anon