try a can of chili for a tasty and convenient meal, full of protien and calories. i think a can of chili, like Hormel, has 40g protien. i heat a can up at work sometimes. add a little cheese, crackers, sour cream, tabasco, onion etc to spruce it up.
another canned food that i have at work that is high in calories and protien is Dinty Moore beef stew. i never tried it before but saw it at Wal Mart for $2 a can. it is surprisingly good. kinda heavy though.