51 Days

Three blondes go into a bar and tell the bartender "Three Martinis,
please."  They raise their glasses and toast "To 51 days."  The 
bartender raises his eyebrows.  The blondes order another round of 
drinks and again toast "To 51 days", causing the bartender to ask 
"What's with the '51 days'?"  One blonde says "It only took us 51 days
 to finish the jigsaw puzzle, and it said 2-4 years on the box."