When's the last time a state had a constitutional convention?

[Meeker]

It seems like there were a number in the 70's and 80's but I haven't heard of one happening in the last ten years or so.

[Small Business Owner of Any Repute]

All the votes that the Massachusetts legislature had about gay marriage happened under constitutional conventions. I can't speak for the other forty nine, but Massachusetts definitely had a constitutional convention in 2006.

[jimrtex]

It seems like there were a number in the 70's and 80's but I haven't heard of one happening in the last ten years or so.

Some states have provisions in their constitution that provide for periodic referendums on holding a state constitutional convention.  In 2010, Iowa and Michigan voters both turned down conventions by about a 1:2 margin.  In Michigan, there was polling in the spring that indicated a favorable vote, and Governor Granholm was reported to be in favor.

This has a list of some more recent successful conventions:

http://www.repaircalifornia.org/about_california_other_states.php

[jimrtex]

All the votes that the Massachusetts legislature had about gay marriage happened under constitutional conventions. I can't speak for the other forty nine, but Massachusetts definitely had a constitutional convention in 2006.

I don't really know that qualifies as a constitutional convention or not - it is simply the General Court (legislature) meeting in joint session to consider petitioned amendments.  I think it is more an odd way of amending the constitution.