Some Tongue-twisters

A tongue-twister is a phrase that is designed to be difficult to articulate properly. Tongue-twisters may rely on similar but distinct phonemes, unfamiliar constructs in loanwords, or other features of a language. They are often used as an exercise to develop a flexible and expeditious diction. Here are some tongue-twisters in the English language. Try to read them. If you know some you can post them as a comment.
Try to say the following at least 5 times in a steady pace:

• A critical cricket critic
• A noisy noise annoys an oyster
• A pale pink proud peacock pompously preened its pretty plumage
• As the roaring rocket rose, the restless roosters rollicked
• Can you imagine an imaginary menagerie manager imagining managing an imaginary menagerie?
• Cows graze in groves on grass which grows in grooves in groves
• Fat dogs frying fritters and fiddling ferociously
• Good blood, bad blood
• I never felt felt that felt like that felt felt
• I never smelled a smelt that smelled as bad as that smelt smelled
• Lotty licks lollies lolling in the lobby
• Naughty Nettie’s knitting knotted nighties for the Navy
• Quinn’s twin sisters sing tongue twisters
• Red leather,  yellow leather
• Slippery seals slipping silently ashore
• The big black-backed bumblebee
• The sixth sheik’s sixth sheep’s sick
• The wild wolf roams the wintry wastes.
• Tom threw Tim three thumbtacks
• Who washed Washington’s white woolen underwear when Washington’s washerwoman went West?
• Yellow Yo-Yo’s

Which one is the hardest? Do you know some? Please, share and post some comments.