Pete Wentz, Playboy Playmates hosting Lollapalooza afterparties

You’ve probably heard about the Lollapalooza 2011 aftershows that were announced last month. Now here’s a look at the afterparties and appearances that have yet to be announced or may not be on your radar:

The Alchemist, Eminem’s DJ, will spin at Underground August 6.

Pete Wentz will perform with his new band, Black Cards, and DJ Aug. 5 at – where else? – Angels & Kings in the Hard Rock Hotel. The rock lounge, co-owned by Wentz, will be expanded into the Hard Rock Hotel’s lobby to accommodate the larger crowds. Like the Underground events, this party will be open to the public.

The Hard Rock Hotel hosted the famous three-day Music Lounge parties the last five years, but this year that honor will go to the W Chicago – City Center Hotel. The parties will be two days this time around, Aug. 5 and 6, and will feature performances by Skylar Grey, Two Door Cinema Club and Fritz and the Tantrums and DJ sets by Grace Potter of Grace Potter and the Nocturnals and former “That 70’s Show” star Danny Masterson. It’s free booze (courtesy of Belvedere Vodka), but is VIP only.

It sounds like “Written in the Stars” rapper Tinie Tempah will perform at an invite-only afterparty for Topshop/Topman clothing store. The party will not take place at the store’s yet-to-open Michigan Avenue location.

Playboy Playmates Crystal McCahill, Summer Altice and Sasha Bonilova will host Playboy’s Yacht Party on Lake Michigan August 6. Chuckie will DJ the $100-per-person midnight cruise.

Lastly, My Morning Jacket’s Jim James and Foo Fighters’ Dave Grohl have been approached about singing the 7th inning stretch at Wrigley Field during Lolla. No word on whether they’ve accepted.