You know my ears perk up when I hear the "A" word!
I've never needed to freeze them, as they're abundant year round here (and if my older boy is around, there'd be nothing to freeze anyway)
I always trust the California Avocado Commission, and here's what they have to say on the matter:
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HOW TO FREEZE AVOCADOS:
When you have an abundance of fresh fruit, consider freezing it. Although avocados are not satisfactorily frozen whole or sliced, pureed avocados freeze very well and can be used in salads, sandwiches and dips.
Wash, seed and peel the fruit as described above.
Puree the flesh, adding one tablespoon of lemon juice for each two pureed avocados. Pack the puree into a rigid container, leaving 1 inch of headspace.
Seal and label the containers.
Freeze and use within four to five months.
Source: California Avocado Commission