There are many free building plans for picnic tables on a wide variety of websites. About.com is a good starting place that can point users to plans that include step-by-step instructions, materials lists and required tools.
A simple Internet search using the keywords "free picnic table plans" yields dozens of reliable websites. Plans range from the traditional six-person picnic table with bench seats on either side to more complex octagonal designs. There are even plans available for complicated folding picnic tables designed to maximize space and efficiency.
Free table plans are often simple line drawings that a skilled woodworker could follow, complete with dimensions for the required lumber. Others are more detailed, step-by-step plans that walk any builder through the process of buying materials, procuring the necessary tools and building the table. Still other plans come linked to buying options for necessary building materials or a completed table should the builder decide to simply purchase a finished product.
Many table plans are accompanied by videos showing the construction in a sequenced manner, which is very helpful for the new woodworker. For most, building a picnic table from one of these free plans is an easy weekend project that is fun to tackle.