This weekend, two very different holy days converge, as Easter and 4/20 both fall on Sunday - Weedster, if you will. Some Christians and marijuana smokers are taking advantage of the coincidence to do some interfaith outreach - pastors are planning 4/20-themed sermons for Sunday, inviting new congregants to try getting high with God instead of drugs. Online, on the other hand, you can learn how to roll a cross-shaped joint with Seth Rogen and make a pot-friendly Easter basket.

All of which got me wondering - just how often does Easter fall on 4/20? The computation of the date of Easter is incredibly complicated and used to be a subject of fierce debate among theologians. But nowadays it's easy enough to boil down to a few lines of computer code or an Excel formula.

In the next 1,000 years, Easter will fall on 4/20 a total of 33 times. This puts it right in the middle of the pack of dates that Easter could fall on. At the top end of the date spectrum is April 6, with 45 Easter occurrences, while at the bottom is April 24, with seven.

The last time we had a 4/20 Easter was in 2003, and it will happen again in 2025. But after that it won't occur again until 2087, which means that this is the penultimate Weedster most of us will experience in our lifetimes.