Usually an election made by a parent for a child.  Used to be a time when buying bonds for a kid was not considered abusive.  This is what Pub 550 says:

Choice to report interest each year. The
choice to report the accrued interest each year
can be made either by your child or by you for
your child. This choice is made by filing an income tax return that shows all the interest
earned to date, and by stating on the return that
your child chooses to report the interest each
year. Either you or your child should keep a
copy of this return.
Unless your child is otherwise required to
file a tax return for any year after making this
choice, your child does not have to file a return
only to report the annual accrual of U.S. savings
bond interest under this choice. However, see
Tax on unearned income of certain children,
earlier, under General Information. Neither you
nor your child can change the way you report
the interest unless you request permission from
the IRS,