I will start by saying I am very new to using Arduino. The project I am planning is to create several arrays of sensors (each array will consist of 4 DS18B20 sensors and one temperature/humidity sensor) and using a MUX connected to Arduino I want to read the data from each [ten] array. I have found sketches I can modify to do this task in a continuous cycle but I need to be able to display data from an array for an extended time period of several minutes. My Arduino will output to a 3.2" LCD so there is only enough screen space to show data for one array at a time.
The DS18B20 is a 1-Wire device and doesn't require a multiplexer, each device has its own address on the bus and you can connect a lot of them with a single wire. Depending on the humidity sensor you pick you may be able to use the same bus for it as well.
It is harder to find 1-Wire humidity sensors, but you could use a DS2438 Smart Battery Monitor which also includes an ADC to give you values from an analog humidity sensor.
The challenge of designing your project will be setting up an easy to understand display and controlling how/when it changes.