Every BB has one.

A hapless nerd who falls for the beauty of the house, who in turn likes the attention but doesn't necessarily fancy him back.

There's been loads. Most memorable for me was lovelorn Marcus fancying Noirin.

Any more?

Sree and Noirin.

Everyone fancied Noirin.

Doesn't really fall into the nerd category... but Adam fancied Lauren in BB13. There were lots of unrequited love relationships in BB13:

Adam fancied Lauren
Luke S fancied Lauren
Luke S fancied Ashleigh
Ashleigh fancied Conor
Lauren fancied Arron a little bit
Arron fancied Sara

Craig and Anthony 4ever.

Other than that and the Sreenoirin, I don't think any of the unrequired love plotlines have been very entertaining; they're usually just depressing. Darnell and Sara being one of the worst.

Freddie fell for Bea.

Didn't Andrew have a crush on Josie ???

Marcus was far from a nerd in my opinion, more of a loner really.

Glyn and Lea. For a gay man he seemed mesmerised by an enormous pair of breasts.

George and Grace maybe?

Can we squeeze Chris and Caroline into this category?

I thought they hated each other or is my memory just completely gone on this?

Ooh also could we kind of add Kara Louise and Ziggy BB8 for when Chanelle left. She seemed enamoured with him.

Quite a large one. I remember a conversation in the snug area with John James talking to Andrew about it.

Ben fancied Rachael 1(Beyonce lookalike).

Also, Freddie said he fancied Sophie at the beginning of BB10.

Luke and Jen BB9
Also not really a nerd but Steve fancied Keeley in BB11.

Caroline certainly loathed Chis. But wasn't the date set up because he had admitted to a crush on Caroline?

Belo and Amanda.

Ahhhh, I thought it was set up as a joke because they both wanted to be put in a "Who will blink first" sort of situation after everyone spurred them on.

Jodie fancied Preston, I think; and was none too happy with the level of requition. (I know it's not a word - but it should be)

Aden and Rebeckah

I know he wasn't strictly speaking a nerd but he was fairly hapless

"I'm me. You're them. What am a meant to do then?"

It seemed to me Jon liked Nush in BB4 and Federico (not really nerdy but with an inquisitive mind) maybe liked Anoushka.

( very off topic but about BB4 - If Jon and Nush, Federico and Anouska and Ray or Gos had been the last five Id probably have found it a more interesting series.
Federico might have stuggled with the endurance of being there for a full series though, and although I was fond of him, his mischief- eg asking Steph personal questions, wasn't conducive to the 'cosy' series that it became, which I think some viewers enjoyed. I read a producer's favourite moment was Steph speaking through the door to Cameron and supporting him- not knowing he was off to Africa.
Perhaps Jon didn't cause mischief on his return because he realised that the storyline developing was that of a woman who had lost faith in men, enjoying developing friendships with two steady and comfortable/easygoing men who were fond of her -Cameron and Gos. It was also quite sweet when Steph had the little ego boost of a sexy guy like Ray telling her ''for God's sake Steph, you're not a minger!'' )

Glyn and Aisleyne was a near variation, though it didn't fit this thread's idea exactly.

Was Nush the blonde who injured her leg during the series??

Not quite. Nush was the blonde who had her leg broken by a mugger a bit after her series (bb4) ended.

One article: http://www.bbc.co.uk/herefordandworc.../08/nush.shtml