The clock technique is an idea mentioned on mnemotechnia.es.
Take an analog clock face and superimpose it on a map. The example given in the article is a map of Spain. Each hour is represented by a city that falls near each hour on the clock face. One can then remember times by attaching images from that city to the thing that takes place at that time.
The technique can further be expanded by using Phonetic Number Systems to represent minutes. That gives a total of 720 mnemonic hooks (12 hours times 60 minutes).