I think it used to be aired in CN (Cartoon Network), it was a series about a pair of twins wearing a striped pyjamas. I think they lived in a groomy mansion or an old big house. I believe they had a sister but I could be wrong about that. A popular girl was the antagonist as she seemed to despise the twins. I believe they were kind of genius as they invented gadgets.
The twins looked somewhat like salad fingers, they weren't actually evil, just mischievous.