How this DM would run the skillful moment spell
This reader suspects that the 1st-level Sor/Wiz spell skillful moment [trans] (Dragon #350 78) is supposed allow the caster to, upon casting the spell, pick a skill then, next round, make a skill check using that skill that normally takes no more than 1 standard action to make. On that skill check, instead of rolling the die, the player treats the die's result as if it were a 20. This would, for example, make it normally impossible for the skillful moment spell to affect a typical Decipher Script or Disable Device skill use or any other skill use that takes more than a standard action to execute, but the skillful moment spell could be employed to roll a 20 on Jump skill check made to clear a chasm or to roll a 20 on a Bluff skill check made to feint.
This is how this DM would have the spell function at his table were a player to need the skillful moment spell to realize his vision for his character. However, like I said, that reading is only what this reader suspects the spell is supposed to do; the spell actually doesn't say it does that, like, at all.
What the skillful moment spell description says
The spell skillful moment says that the caster casts the spell and picks a skill, like, for example, the skill Escape Artist or Search. Next round, the caster takes a standard action to take 20 on one of that picked skill's skill uses. However, the—for lack of a better term—double-secret limits of the skillful moment spell as the spell's written are rooted in (buried in, really) the fact that, although the caster is going much more quickly than normal, the caster is still taking 20 on the skill check. Seriously, the spell's description really says, "On the round after you cast this spell you may take 20 on the chosen skill as a single standard action," and taking 20 says
When you have plenty of time…, you are faced with no threats or distractions, and the skill being attempted carries no penalties for failure, you can take 20. In other words, eventually you will get a 20 on 1d20 if you roll enough times. Instead of rolling 1d20 for the skill check, just calculate your result as if you had rolled a 20. Taking 20 means you are trying until you get it right, and it assumes that you fail many times before succeeding.… Since taking 20 assumes that the character will fail many times before succeeding, if you did attempt to take 20 on a skill that carries penalties for failure…, your character would automatically incur those penalties before he or she could complete the task…. Common "take 20" skills include Escape Artist, Open Lock, and Search. (Player's Handbook 65)
(Emphasis mine.) In other words, in that skillful moment that the skillful moment spell creates, the caster takes 20 normally but taking only a standard action to do so rather than taking twenty times as long as the skill use would usually take. This means that, for example, the DM can rule that during the spell's skillful moment the caster's die rolls were nineteen 1s then a roll of 20.
Thus the spell's take 20 language forbids the spell's use in conjunction with any skill use that can't typically be tried again (e.g. typical uses of the skills Appraise, Climb, Decipher Script, Diplomacy, Disable Device, Jump, Perform, and Profession). This also means that generally excluded are any skill uses requiring an opposed skill check (e.g. typical uses of the skill Bluff, Forgery, Hide, Listen, Move Silently, Sleight of Hand and Spot). This also means that if each skill use has an associated cost—a use from a healer's kit for a Heal skill use, for example—that cost must be paid 20 times.1
Due to the excessive baggage that comes with taking 20, this reader strongly suspects that the spell wasn't meant to be played this way, despite the spell's description saying what it says. That is, read this way, the spell skillful moment becomes irrelevant for the vast majority of tasks, leaving available only a handful of niche no-penalty-for-failure-that-are-also-unopposed skill uses like (and these examples should come as no surprise) typical uses of skills Escape Artist, Open Lock, and Search.
1 This DM typically allows taking 10 but not 20 on Craft skill checks. A Craft skill check's result represents progress toward a goal, and once progress is made, there's no way to, like, undo that progress and restart from where the craftsman left off before having made that progress! While I'm certain we writers and you coders could have a spirited debate about how this lacks verisimilitude, bear in mind that this is for a fantasy game that's usually concerned with creating stuff like alchemist's fire and greatswords rather than, like, recovering from a tragic hard drive crash.
