In the episode "Ignition", he discusses his fascination with jet packs, even going so far as to show Gibbs a film he has made about them (produced under his pen name "Thom E. Gemcity", an anagram of Timothy McGee).
McGee's writing has given him enough fame to be feted as a minor celebrity and he can enjoy perks such as VIP clubbing, as seen in the episode "Friends and Lovers".