quick answer

There are so many ways. (1) By will, expressly disinhereit your spouse. If you live in community property states, you can transfer your 1/2 plus your separate property to anyone you want. (2) By an inter vivos trust with a spendthrift provision, naming your kids as beneficiaries, so that no other people can touch it. (3) Pour over trust through your will. (4) Gift. (5) Todden trust. (6) Purchase annuity/life insurance for your kids, naming them as beneficiaries. (7) Purchase US saving bonds, naming kids as beneficiaries so that state probate code would not apply. (8) UTMA. UTMA would be the easiest way but it has problems. Talk to a professional to find out pros/cons of each option.