Rodney Clapp has a great article at Christian Century about why we need people to pray for us. This is what I bring into the jail. When people tell me they are having a hard time praying, I tell them about the people outside who are praying for them. "Let their prayer carry you for a while."
If they are bored with their own prayers, their own concerns, I give them a name of someone outside and say, "Here's someone who needs your prayer." It is a wonderful exchange, a purposeful act. Go read what Rodney Clapp has to say about it.