spamgourmet provides disposable email addresses that get created automatically the first time they are used, forward messages, and then automatically expire.
B. Krause, C. Schmitz, A. Hotho, and G. Stumme. AIRWeb '08: Proceedings of the 4th International Workshop on Adversarial Information Retrieval on the Web, page 61--68. New York, NY, USA, ACM, (April 2008)