When the skills were streamlined for 4e D&D one of the skills that disappeared was Craft. That’s not to say that PCs can’t create things anymore, it’s just that this kind of task isn’t something you’re likely to use very often. It’s a task more suited for an NPC, not an adventurer.
However, there might still be times when you do want to create something yourself. You might require a unique device to accomplish a goal, you might need to pose as a smith or carpenter, or you might need to craft your own weapon as the first part of an epic quest.
When PCs find themselves in this situation the DM needs to determine just how significant the outcome is going to be. If it’s just something you’re doing during your down time then no role playing is probably required. In fact no roll is likely required either. However, if the success or failure of your handiwork will affect the outcome of things to come, then perhaps it’s time to turn your labours into a skill challenge.
If your gaming group is anything like mine, rituals are the most under utilized aspect of 4e. Since the release of the newest edition of D&D, I’m not sure if one of our PCs has ever used a ritual. For me, this is because I’ve played PCs who aren’t trained in ritual casting for our long term games. When I have played PCs who have the feat, it’s been for one-off Dungeon Delves, which don’t normally require the use of rituals to progress through to the end.
Defeating a Lich is not a simple as overcoming it in combat. Liches tie their life force to objects known as phylacteries. The phylactery can range from mundane to mystical. Each Lich has their own preference on what constitutes an acceptable phylactery. What Liches have in common is that their Phylactery is to be well hidden and well protected.