Never been to IKEA on a Thursday but wonder if they do pea soup and pancakes. Used to eat that a lot when I was working over there. No-one ever did explain to me why every canteen seemed to serve it on a Thursday though.
Wikipedia talks about this. Mentions that Sweden and Finland both have a tradition of serving pea soup on Thursdays since at least the 13th century as a preparation for fasting on Fridays.
Personally, I hate Ikea meatballs and gravy both. I like most things, but white pepper is one thing I really dislike. From the taste, both meatballs and gravy have huge amounts of it.