Q: My son is a Marine deployed in Iraq. He will have a two-week leave in August and plans to meet a friend in London. They are interested in the party scene and have no idea about accommodations in and around the city. Can you offer these two wild and crazy guys some guidance?

A: The guys have chosen a great place to unwind. London has plenty of clubs, bars, live music and comedy nights to keep them entertained. Yes, the city is expensive, but there are ways to get around that: staying in hostels or guesthouses, eating at ethnic restaurants, attending free choral concerts at churches. Just kidding on that last one.

The boys should stay in the city for optimum access to the action. They can avoid hotel sticker shock by checking the lists of (relatively) affordable accommodations on sites such as London Budget (www.londonbudget.com/accommodation).

One recommendation: the Gate Hotel, a 19th-century townhouse in a particularly lively area of Notting Hill Gate, which is one of the trendiest areas in London at the moment. It has double rooms from about $130 a night. The city’s official tourism site, Visit London (www.visitlondon.com), is another terrific source for bargains, with exclusive offers.

London’s hostels, by the way, are not the vaguely seedy dormitories of yore but lively, modern digs, many in prime locations and with private rooms. The Visit London site has a good Top 10 list based on guests’ feedback.

To scope out the ever-changing party scene, Time Out London (www.timeout.com/london) is a must, with recommendations by date and category (Bars&Pubs, Clubs, Comedy, etc.). The Visit London site is another great resource.

For more recommendations, check an online forum such as those at TripAdvisor (www.tripadvisor.com) and Lonely Planet’s Thorn Tree (www.lonelyplanet.com/thorntree).

Q:My wife and I are taking our 13-year-old grandsons out West. What identification do we need for them to travel via air, since they have different last names from each other? I understand that the Transportation Security Administration has changed some rules, but I cannot find rules for traveling with minors within the United States.

A: You might be thinking of the recent requirement that air travelers 16 and older have passports to travel between the United States and Mexico, Canada and the Caribbean. The rules haven’t changed for minors traveling domestically, though: Identification is not required for those younger than 18. The fact that your grandchildren have different surnames doesn’t affect this, said TSA spokesman Greg Soule.

Having said that, it would be a good idea for you to carry copies of your grandsons’ birth certificates (or passports, if they have them). Some people also carry notarized letters from the children’s parents giving permission for the trip. These documents aren’t necessary from an airline security standpoint but could be helpful in an emergency.