Linq Select 5 items per Iteration

It sounds like you want the Batch operator from MoreLINQ:

foreach (var batch in query.Batch(5))
{
    foreach (var item in batch)
    {
        ...
    } 
}

for (int i=0; i < 20 ; i++)
{
    var fiveitems = theList.Skip(i*5).Take(5);
}