Yes, but I can't for the life of me remember what number it is. It's the episode where Kururu was going to be leader for the day, and Keroro and Co. couldn't find him. They called Aki, since they knew Kururu has a soft spot for her (enter...this picture) and she was on a spa vacation with the kids, showing them a free pass that Kururu had given her.
If you go on wikipedia, and look up "List of Sgt. Frog episodes" you should be able to find it in one of the middle or later seasons. The title of it is something like: "Kururu: Leader for a day".
I may be able to find it for you, but I feel too lazy and tired right now, honestly. ^_^
They have it on Netflix, but it might just be the last season now. I started out watching it that way too, but then I picked up watching them on youtube. There are like...300 odd episodes. I started liking the Japanese version (with subtitles) much more than the English. But if you don't watch anime a lot you won't care.
Cool! I just like the Japanese Keroro Gunso the best, because I've watched both too, and usually when you watch the English, they roughly translate it the same... But, the English "Sgt. Frog" totally butchers the original. It's pretty much a spoof of what it should really be. It's like when they make those spoofs of Dragonball Z online, only they turned it into the actual anime. It's awful. They wanted to Americanize it, so they put in a whole bunch of American pop culture, even though it's a Japanese show.
From 311. It's Kururu's turn to be "invader leader for the day" and he got rid of his weaknesses to freak everybody out so they think he would do something dastardly. This was actually imagined in Keroro's head when he was mentioning how Aki is a weakness to him.