Egypt - The uprising in the African nation continued Friday as police fired tear gas into crowds in an attempt to disperse thousands of anti-government protesters. Vans filled with riot police circled Cairo neighborhoods before Friday afternoon prayers, and opposition leader Mohamed ElBaradei was placed under house arrest, a high-level security source told CNN on Friday. Keep up with minute-by-minute action right here at "This Just In."

Meanwhile, in other nations, protests broke out in the Jordanian capital, and an opposition party in Albania pushed for more protests in Tirana. Analysts said the widespread protests are part of a ripple effect that began last month in Tunisia.

Challenger - It’s been a quarter-century since the space shuttle Challenger exploded 73 seconds into takeoff, killing the six astronauts on aboard and teacher Christa McAuliffe. The disaster grounded the space shuttle program for three years. NASA Television will air a remembrance service honoring the crew, and June Scobee Rodgers, the widow of Cmdr. Dick Scobee, will be among the speakers. CNN will also talk to a former neighbor and Sunday school pupil of McAuliffe’s, who says McAuliffe inspired her to become a teacher. Be sure to check out CNN’s full coverage page, Remembering Challenger.

Davos - World leaders, economists and business people continued gathering Friday in Switzerland to discuss the global economy. The theme this year is “The New Reality.” Last year’s World Economic Forum in Davos focused on financial reform. CNN will explore whether reforms have made the global banking system more stable.

This year, a “little explosion” at a hotel and French President Nicolas Sarkozy’s defense of the euro already have made headlines.