Historical clue formulations

• Many Rice grads: Abbr. — 2008-10-19
• Hwy. planners — 2008-01-17
• Many Rice grads: Abbr. — 2007-12-16
• Boeing personnel: Abbr. — 2007-08-11
• Corps personnel: Abbr. — 2007-02-24
• R.P.I. grads — 2000-07-30