Originally Posted by Canarsie
If you are a Hilton HHonors member, you could stay at a Hilton HHonors property without setting foot on an airplane and still credit your Delta Air Lines SkyMiles account with either 500 SkyMiles or 100 SkyMiles, either of which will keep your account activated for an additional three years.
Or if you rent a car (like from Hertz), you can choose to collect miles and post them to your SkyMiles account. It will cost $0.50 per day (in addition to the rental costs) but you'll extend your account status also.