If your New Year's resolution led you to take up running, you have just enough time to train for a spring time marathon to prove your dedication. Classic Tours (020 7619 0066) has a number of holidays that include guaranteed marathon places, including the Paris marathon, 14-16 April, the Dead Sea marathon in Amman on 11-14 April and the more adventurous Beijing marathon, 19-23 October. Packages from £1,100pp.