SLIPPERY ROCK — The Slippery Rock Heritage Festival takes place from 10 a.m. to 4 p.m. Saturday at Slippery Rock University.

The festival is held each year to promote the history of Slippery Rock and surrounding communities. The memory area will be in the Alumni House; participants may take memorabilia.

Performers will include Crossroads Dance Academy, the Tamarack Lake Cloggers and the Sanctuary Jazz Band. The pet parade will begin at 1 p.m. There will also be a car cruise.

Admission and parking are free. There is a fee to register for the car cruise.

Visit www.slipperyrockheritageassociation.org.

CENTER TWP — Lawrence Rihel Jr. will be signing copies of his whodunit book "The Dazzling Detective" from 1 to 4 p.m. Saturday at Borders Express, Clearview Mall.The author, born and raised in Butler, released the 149-page softcover book earlier this year.

PITTSBURGH — Carnegie Science Center will welcome veterans of the USS Requin as they reunite and share stories with visitors Saturday.The USS Requin is the submarine docked in the Ohio River outside the Science Center.The crew holds its reunion every three years, and about 50 veterans and their spouses are expected to attend.Also Saturday is the submarine's last behind-the-scenes tech tour of the summer. Cost of the tour is $12 for members and $15 for nonmembers. To register, call 412-237-1637.Any visitor wishing to go on a self-guided tour may do so daily from noon to 5 p.m., weather permitting, for a walk-up fee of $5.

PITTSBURGH — The Pittsburgh Irish Festival's 20th anniversary Celtic Celebration will be held Sept. 10 to 12 at the Riverplex, 1000 Sandcastle Drive.Performers will include Gaelic Storm, Scythian, Makem and Spain Brothers, John Doyle Trio, Glengarry Bhoys, Screaming Orphans, David Kincaid and Cahal Dunne.Adult admission is $10 in advance or $12 at the gate. Students with ID pay $8 as do senior citizens older than 60. Active or retired military with ID are admitted for $5, as are public safety officers with ID.Call 412-422-1113 or visit www.pghirishfest.org.