Sorry if it's slightly like a word problem, but what the hell...............:
(One person is telling the truth, the rest are lying)
Bob: Before tomorrow will be Monday. Jill: 3 days in the future, will be 8 days from yesterday which was Wednesday. Chris: It's Tuesday! Poppy: In 3 days, we will have snow, which is forcasted for Monday. Danny: It's Tuesday! Katey: Typical, my birthday is tomorrow and I'm going to an Irish Festival, on Sunday!