Combining two runes will give you a random rune of the same tier. Combining 5 runes will give you a random rune of the next highest tier. You cannot combine 5 tier 3 runes at once (as there is no tier 4).
The rune combiner is random. It doesn't matter whether you combine marks, glyphs, seals, or quintessences -- they all work with each other, and the output can be anything.
The idea is that, generally, runes themselves are priced such that it is slightly cheaper to generate a tier 3 runeset from your old runes than by buying the tier 3 runes on their own. For instance, the level 1 +AD rune is 15 ip, while the level 2 +AD rune is 80 ip -- if you bought 5 of the level 1 runes, combined them, and wound up with a level 2 +AD rune, you would have saved yourself IP.
Unfortunately, as mentioned earlier, this process is completely random. If you have tier 1 and 2 runes, by all means, combine them to higher levels; the rune combiner is just a way to possibly recoup the IP you spent on runes you no longer find useful, but it cannot be counted on to give you what you want. You might luck out and combine 2 random runes into a +Dodge quintessence (very expensive!) -- or you might get a mana/5 Mark (with a tertiary stat, and probably not worth the IP cost of your combined runes).
It's very much a gamble, and you don't get anything exclusive from it, so use it if you need to get rid of T1 / T2 runes, and safely ignore it otherwise.
Champion level and time spent in the game are the main factors - longer games = longer death timers; higher level = longer death timers.
On Summoner's Rift time spent dead scales from 12-50 seconds as Wiki says.
There isn't a calculated formula for champion death time, at least not one known by the players.
There are some ways to reduce this time. Utility tier one mastery Good Hands reduces death time by 4% / 7% / 10%. Each Quintessence of Revival reducse death time by 5%. There is also the summoner spell Revive which instantly revives your champion.
Different maps have different death timers as well. From shortest to longest:
- Dominion
- Proving Grounds
- Twisted Treeline (3v3 map)
- Summoner's Rift (5v5 map)
Best Answer
There are currently no plans to ever make this information available. Riot employees review all cases that result in a permanent ban, and they reviewed EVERY case when the tribunal was first released. You gain IP not for voting the same as the rest of the community, but for voting how Riot's staff would vote. Admittedly, not every case is reviewed by Riot anymore (those that just give out warnings) but players who are still voting in the tribunal today are those who voted in accordance with Riot's policy since it first came out.
Just ask yourself how a Riot staff member would vote on the case you are reviewing, and do likewise.
Remember that the 5 IP bonus as an incentive is still fairly low for the time invested. If you want to make easy IP, it's faster to simply play several bot games (under the new AI update, rewards are decent) The IP rewards are there to avoid making players who are dedicated to the tribunal feel like they are wasting their limited playing time.
Everything Riot has posted about the Tribunal since the dawn o' time:
http://na.leagueoflegends.com/board/showthread.php?t=1127837