At the end of each week, #Top40Tweets lists a cross-section of artists on the current pop charts and puts their tweets on display (along with their current chart number) for your enjoyment/scrutiny. This week, we look at 5 artists on the Billboard Music Charts.

#15: Rihanna – Where Have You Been?

I always thought Rihanna’s self-esteem was low, given her ongoing relationship with Chris Brown, but this self-portrait just hammers it home.

FUN FACT: The trash mags are reporting that Rihanna has been sexting Robert Pattinson since his unceremonious split with K-Stew. SCANDALOUS.

(Uncharted): LMFAO – Sexy And I Know It

RedFoo finally references the fact that he’s actually a 37-year-old man, and he’s in a party rap band with his nephew.

FUN FACT: LMFAO love referencing their gentials in their lyrics. [READ MORE]

#32: Wiz Khalifa – Work Hard, Play Hard

Whoa, let’s not get crazy. Next, Wiz is gonna start mixing Lucky Charms with Fruit Loops. Remember the old adage: “Loops before Charms, you’re asking for harm. Charms before Loops, you’re gonna poop.”

FUN FACT: Wiz Khalifa was shocked by the backlash he faced when he revealed the album cover for O.N.I.F.C.. I can’t imagine why.

(Uncharted): Ke$ha – We R What We R

You think the “penis” nail is the focus of this picture, and then you realize her middle finger is growing a giant white tumor.

FUN FACT: There’s no title or release date yet, but Ke$ha’s new album is nearing completion. According to Dr. Luke, the album’s executive prodcucer, we’re “going to hear an artist that’s grown and is evolving, but it’s Ke$ha. She’s no choir girl yet.”

#5: Katy Perry – Wide Awake

No one who married this man could possibly be considered human.

FUN FACT: Apparently John Mayer and Katy Perry have broken up already, after a short-lived summer fling. If Katy’s body is indeed a wonderland, John Mayer didn’t get that much value out of his season pass.