Conversation so far:
When did Weezer go on hiatus?
Weezer completed the Pinkerton tour in mid-1997 and went on hiatus until Weezer reunited in April 2000.
What did some of the artists from Weezer do when they left on hiatus between mid-1997 and April 2000?
Drummer Patrick Wilson returned to his home in Portland, Oregon to work on his side project, the Special Goodness.
What did Brian Bell do during Weezer's hiatus between mid-1997 and April 2000?
Guitarist Brian Bell worked on his band Space Twins during Weezer's hiatus.
What did Matthew Kelley Sharp do during Weezer's hiatus between mid-1997 and April 2000?
Bassist Matt Sharp left Weezer to complete the follow-up album for his group the Rentals.
What did Rivers Cuomo do during Weezer's hiatus between mid-1997 and April 2000?
Frontman Rivers Cuomo returned to Harvard to focus on songwriting. He formed a new band composed of a changing lineup of Boston musicians and performed new material.

Question: When did Weezer reunite with each other?
Self-contained rewrite: When did Weezer reunite with each other after Weezer's hiatus between mid-1997 and April 2000?