Now then, guys and gals

It's me Birthday next week and every year since I can remember I've had a BBQ with me mates to celebrate it. However, as it seems we can no longer rely on the weather in August and I fancy a bit of a change, I'm looking for your help.

I want to cater a curry, preferably lamb, for about 30-35 guests.
The curry will have to be mild to middle of the road for some of the guests, I reckon on having cream to add if it's too hot, and plenty of chillies for those who want extra pep. I can lay my hands on a very large cooking pot but am a little lost on a good tasty recipe for so many.

Any help would be appreciated

Cheers in advance.