D.C. American History Museum reopens

Christmas just came early for anyone who wants the gift of free city-to-city travel. Starting today, Megabus is giving away 100,000 free seats on its express buses for trips between Jan. 14 and March 18 on all Megabus routes—29 cities in the Midwest and Northeast. Book your free seat at megabus.com using the promotion code "greenbus." Availability is based on a few factors (like how many other passengers got free tickets on the same bus or on the same day), so if there isn't a free seat available on your first choice, try switching the departure time or the day, if your dates are flexible. It should be noted that Megabus allows travelers to book only a few months in advance, so you won't be able to snag a free seat today for a trip in April. Each day Megabus opens up itineraries for one day further out: Today, you can book through Jan. 24. Tomorrow, you can reserve a seat through Jan. 25, and so on. You can book by phone, too (877/462-6342), for the same dates available on the site that day. A BT hint: If you're on the hunt for tickets on a specific departure date this spring, mark your calendar to check back when Megabus'll be opening those schedules. Megabus was one of the winners of Budget Travel's 2008 Extra Mile Awards. (Additional reporting by Kate Appleton)

The Canadian short-haul regional airline Porter has begun flying roundtrip from Toronto to Chicago three times a day during the week and twice a day on weekends. As of January 8th, service increases to six daily workweek flights. Porter differentiates itself by flying directly to the downtown Toronto City Centre Airport, rather than the less convenient Pearson airport. (Porter's new Toronto-Chicago service happens to also reintroduce international service to Midway airport.) Bucking recent economic trends, the airline promises to expand service to Boston, D.C., and Philadelphia over the next three 18 months. Porter uses new turboprops that offer custom leather seats with two to three inches more legroom than the 30 inches of legroom you typically find in the economy-class sections of other airlines.

A stress-free airport experience is becoming less of a wishful fantasy and more of a reality thanks to paperless check-in with many smart-phones and PDAs. It started first with Continental Airlines. But now, others like British Airways, Delta, Northwest, Southwest, Air Alaska Alaska Airlines, and Air Canada are slowly rolling out a way for customers to check-in for a flight, via Web-enabled devices like iPhones and Blackberries. How to do it is all relatively similar between airlines, but not uniform. Delta allows the boarding pass to be scanned directly from your mobile device. Register your cell phone number to receive a text message with a boarding pass bar code. Then hold up the screen of your cell phone under the airport security scanner, rather than show a paper boarding pass. (As always, you have to present a government-issued photo I.D. too.) Delta is testing the service at LaGuardia Airport. Similarly, passengers on American airlines on nonstop domestic flights from Chicago O'Hare, LAX, and Orange County John Wayne Airport can now check-in at AA.com and choose to receive an electronic boarding pass via e-mail, in the form of a two-dimensional bar code. (For details and photos, visit aa.com/mobileboarding.) In contrast, British Airways offers to fax the boarding pass, send it directly to an airport kiosk or check-in desk, or send it in an e-mail to be printed later. —Meagan Drillinger

The Intrepid Sea, Air & Space Museum will reopen this weekend in New York City after nearly two years of renovations. The ship, launched in 1943, belonged to the Navy's Essex-class carriers, renowned for helping to win WWII. The Intrepid fought in almost every major battle (and survived many kamikaze attacks), then went on to serve in the Vietnam War and recover NASA space capsules before retiring in 1974. In 1982, the museum opened aboard the ship. In 2006, the Intrepid departed its home on Pier 86 to go to Staten Island and New Jersey for renovations (after getting stuck in the mud). The entire project, which included rebuilding the city-owned pier, has cost about $115 million. After all that, it's time to celebrate. The grand reopening begins on Saturday; the first 1,000 visitors will get a commemorative coin. You can see the new interactive and multimedia displays at the museum, which is devoted to period aircraft, artifacts, and the life stories of the soldiers who fought in the wars. Plus, there are fireworks scheduled for Saturday night. The fun continues through Tuesday, which is Veteran's Day. Fun trivia: it took 7,000 gallons of paint to cover the 27,000-ton carrier. Pier 86, 12th Ave. and 46th Street, 877/957-7447, intrepidmuseum.org. Get detailed directions here. General admission $20. Open Saturday 10 a.m.-8 p.m., Sunday and Monday 10 a.m.-6 p.m., and Tuesday 2 to 6 p.m. (last ticket sold at 5 p.m.).