It seems like the word 'unlimited'  has a very different meaning to mobile service providers in Kenya.

This is what Airtel tells you about its Club 10 tariff and the supposed 'unlimited' calls:

[caption id="attachment_5641" align="alignnone" width="538" caption="Sourced at: africa.airtel.com"][/caption]

But this is what they give you: 60 FREE minutes to be used between 10.00 p.m and 6.00 a.m. When these minutes are exhausted, you will be charged at the normal rate of KES 3 per minute.

A customer went ahead and complained this morning on twitter. See the conversation.

@Kelmunyasia You call airtel number for 60 freeminutes between 10pm and 8am

— Airtel Kenya (@Airtel_KE) April 25, 2012

Update: The 'Unlimited SMS all day' are actually 100 SMS